Urban residential buildings consume a large amount of energy. In most homes, heating runs on a set schedule. Therefore, the installation continues to operate irrespective of whether the residents' thermal comfort requirements have been fulfilled. This process results in considerable wasted energy and CO emissions. To address this issue, in this study, data on heating energy use and carbon emissions from 2302 field surveys in the core, main, and suburban areas were quantified. Furthermore, the impact of different thermal comfort requirements on the carbon emissions of self-heating households was explored based on the PMV-PDD model. The study revealed that (1) Beijing's per capita household energy consumption is 613.80 kgce·a, and heating accounts for a significant portion of energy consumption and carbon emissions; (2) carbon emissions from household energy consumption differ among districts in Beijing, with suburban districts emitting approximately 1.6 times more than main urban areas; (3) suburbs have less need for thermal comfort, but they emit more carbon than other areas with similar heating costs due to limited heating infrastructure, poor access and the high cost of clean energy; and (4) warmer thermal comfort requirements elevate energy consumption and thus positively impact heating costs and carbon emissions, especially in the main urban area. The energy waste caused by heating is quantified, and the impact of thermal comfort requirements on carbon emissions is clarified. The findings are informative for optimizing energy use in residential buildings and proposing targeted low-carbon heating policies.